How do rockets fly in the vacuum of space!?

[Plastic Pilot]

Hi kind sires,

Just fund a video on youtube that was quickly deleted a few days ago about how all the space programs and rockets are a hoax. It explained how rockets can't fly in space by today's technology, like reaction engines, solid fuel, or thermonuclear technology.

I told my father whom is a chemical-biological engineer, and never saw the man with that expression on his face... just went blank for 5 seconds and then tried to figure out how it is possible for the fuel driven technology to produce and induce movement in perfect vacuum and total lack of gravity or other type of electromagnetic field....

The video is no more on youtube, but fund out some other material.


La la la la lie...

 

[Jakko]

There is no "total lack of gravity" in space, and certainly not of electromagnetic fields.

Rockets can fly in a vacuum for the same reason they (and jet engines) can fly in atmosphere: they push mass out the back of the engine. That means Newton's third law of motion ("every action has an opposite but equal reaction") applies: the mere fact of the engine pushing gas out the back, means the engine will be pushed forward.

The reason to use a rocket in space, rather than a jet engine, is because a rocket carries its own oxidiser and all of its reaction mass (namely, fuel plus oxidiser), while a jet engine sucks both oxidiser and most of its reaction mass in through the front (namely, air). Because there is no air in a vacuum, a jet engine naturally won't work there.

 

[Edbert]

chemical/biological =/= aerospace

(my dad worked at NASA from 1961 to 1974)

 

[Jim62]

The real problem is that darned radiation belt that surrounds the earth.

 

[blakeh1]

There is no "total lack of gravity" in space, and certainly not of electromagnetic fields.

Rockets can fly in a vacuum for the same reason they (and jet engines) can fly in atmosphere: they push mass out the back of the engine. That means Newton's third law of motion ("every action has an opposite but equal reaction") applies: the mere fact of the engine pushing gas out the back, means the engine will be pushed forward.

The reason to use a rocket in space, rather than a jet engine, is because a rocket carries its own oxidiser and all of its reaction mass (namely, fuel plus oxidiser), while a jet engine sucks both oxidiser and most of its reaction mass in through the front (namely, air). Because there is no air in a vacuum, a jet engine naturally won't work there.

^Yep,

and for that same reason, if an astronaut was to shoot a gun in space it would propel him backwards.

Also to add...if there was no gravity effects in space, nothing would keep planets in orbit, black holes would not exist, planets would have never formed etc..
Also once in motion, it will never slow theoretically slow down unless captured by a strong gravity field. Gravity assist is also how they "sling shot" things into the outer solar system without wasting as much fuel to boost instead

and interesting tidbit is "weightlessness" experienced by Astronauts is actually , more like a form of free-fall. They still have the same mass

 

[Belugawrx]

The real problem is that darned radiation belt that surrounds the earth.

The real problem is the junk we're leaving orbiting this ball...